If you are really cheap on computer, get at least an AMD A12... it's the only APU with 4 core and an Radeon R7 integrated in it. The R7 does a job quite similar to a GT 1030, and should be enough for Overwatch in low or middle. Or get a small Ryzen for obvious future upgrade possibilities and a small RX 540 (they are a bit cheaper than GT 1030) or RX 560 for decent quality.